In the past, preformed vinyl skin shells of a synthetic resin material, such as polyvinyl chloride resin, have served as the outer surface of finished products. The vinyl skin covers the entire inner surface of the typical open pour-type mold cavity section, in order to keep molds clean after removal of the molded products. The entire skin shell is then covered by pouring an expanding urethane foam formulation thereon. A mold lid is placed on the mold cavity section. Typically, it supports an insert member that backs the skin shell in spaced relationship therewith. The urethane foam is spread between the skin shell and insert to bond them together. Thereafter, particular sections of the vinyl shell and any adjacent foam must be cut out or trimmed at openings in the insert that define required openings in the finished products for various associated add-on components, e.g., radio speaker, odometer, etc., in automotive instrument panels. Such cutouts or trim constitute waste sections.
In order to block out flow of an expensive foam formulation at a particular waste section between the skin shell and the insert, lower cost precast rigid foam blocks are sometimes used to fill cavities in the pour mold for the instrument panel insert. These rigid foam blocks are used as fillers to displace any foam that would travel into the waste sections during the final pour stage in the manufacture of a finished product such as an instrument panel. After foaming and removal of the final product, the skin is cut and the rigid foam blocks are removed and discarded.
U.S. Pat. No. 4,968,465, issued Nov. 6, 1990 to Rhodes, Jr. discloses another method of containing foam during molding of a foam-filled product. The patent discloses a mold assembly for molding vinyl skin shelled covered and foam filled products wherein waste portions or the shell and foam are eliminated from }he molded product. Compressible foam or silicone rubber gaskets or spacers of predetermined shape, such as the shape of an opening suitable for a radio speaker, are placed on a skin shell in the mold and compressed between the mold lid and the bottom surface of the mold cavity. The gasket is generally cylindrical. An insert is attached to the upper lid mold half and a vinyl skin is placed on the lower mold half. The gasket is placed on the lower mold half on end in an opening of the skin. The foam is poured and thereafter the mold is closed. After foaming, the gasket is removed. The gaskets of the '465 patent do not provide a peripheral edge for sealing around an extended length bezel surrounding large area openings for instrument clusters and the like.
At the present time, a seal arrangement of paper, tape, foam tape, and a large piece of cardboard is used to plug and seal such bezels and instrument cluster area openings in the instrument panel. Such a sealing arrangement requires substantial installation time. Moreover, it may tear so as to allow foam to leak into a large waste section cavity within the pour mold, created by the shell on the outer surface of cavity of the pour tool and the insert and lid surface of the pour tool creating the upper surface of the cavity. The foam leakage can, in some cases, constitute a substantial percentage of the total foam pour. As a consequence, voids or fatty foam can occur in the instrument panel behind the skin.